As one Bangladesh wicket fell after another on Sunday, the Afghanistan players could scent a historic win. At the end of the fourth day's play, they found themselves just four wickets away from a famous victory in Chattogram.

Amid all that joy, however, there was a question on wicketkeeper Afsar Zazai's mind. Where was Soumya Sarkar, who opened in the first innings, and why didn't he show up in one of his usual top-order positions?

"I was asking one of their batsmen if Soumya Sarkar was injured. He said no. Then I asked why he didn't come out to bat, but he didn't give me the answer," Zazai said.

Indeed, Soumya was sent all the way down at No. 8, the plan being to accommodate three right-hand batsmen in the top four. Mohammad Nabi was seen as the first major threat, and Bangladesh, to their credit, managed to see off his first spell of ten overs without losing a wicket.

But in turning all their attention on Nabi, they were exposed to the wristspinners at the other end, as left-armer Zahir Khan removed Liton Das and Mosaddek Hossain soon after the tea break. Liton played back to a delivery that spun into his pads, while Mosaddek was caught at long-off, miscuing an ambitious inside-out shot. Rashid Khan then snared Mushfiqur Rahim, the third right-hand batsman pushed up the order to tackle Nabi.

With three right-hand batsmen gone, there was no more variety left in Bangladesh's batting, and by the time Mominul Haque was trapped lbw by Rashid, the hosts' plan to thwart Nabi had backfired.

Shakib Al Hasan, the captain, said that he initially planned to send both right-handers - Liton and Mosaddek - to open the batting but was talked out of it by the others in the team management.

"We changed the batting order because to chase 400, we needed to do something different," Shakib said. "If we were chasing 200, we wouldn't have changed the batting order. We made only 200 in the first innings, on the same wicket. We make plans to do something good. When it works, we say, 'wow, what a plan'. When it doesn't, it seems the plan is wrong.

"Their first threat was a pace bowler and Nabi from the other end. The pace bowler will try to bowl economically for four or five overs, get the ball a bit older. Nabi's job would be to get one or two breakthroughs. He didn't get a wicket in the first spell, so we were successful. But we didn't get the big innings that we expected from one of the top four. If the decision was only mine alone, Mosaddek and Liton would have opened the batting. But after discussions with everyone in the team meeting that this should be our batting line-up, we came to the ground."

Shakib said that sending Mosaddek to No. 3 wasn't just to negate Nabi, but because he had a strong first-class record with three double-hundreds and two more scores of 150-plus.

"To be honest, he (Mosaddek) looked the most comfortable among our batsmen against spin in the first innings," Shakib said. "We planned last night that he should bat up the order because of the way he batted in the first innings, and the experience he has of playing long innings having scored a few double-hundreds in first-class cricket.

"If we are to chase 400 or 500, we need a player to play a big innings. At the same time, Nabi is more effective against left-handers, so we wanted to have a left-right combination, which was another reason to promote him. He batted well but he couldn't execute that shot. If he had hit it along the ground, he would have got four runs for it. Things would have been different if he was around for longer."

The ill-timed shots aside, Bangladesh are also close to losing because of a pitch that is highly favourable to spinners, something even Zazai was surprised by.

"We thought they would make a flat batting wicket," Zazai said. "A month and a half ago, I played against Bangladesh A, and the wicket was flat. We thought it would be the same here. We were surprised to see less grass on the wicket. Then we thought we can beat them on this wicket. It will turn after two days."

Mohammad Isam is ESPNcricinfo's Bangladesh correspondent. @isam84